It can’t be easy, being a lifeguard at a pool full of children. The kids that catch your attention are going to be the ones who are splashing and yelling, whereas the ones that you really need to look for could be silently slipping below the surface, where they won’t be seen or heard. North Carolina-based emergency physician Graham Snyder decided that those potential drowning victims needed more attention drawn to their predicament, so he created the Seal system.